Sulfoxide containing detergent compositions



SULFOXIDE C(DNT AHNIN G DETERGENT QOMPGSiTIONS Irving D. Webb, Rosamond, Qalii, assignor to Union Oil Company of California, 'Los Angeles, Calif., a corporation of Caiifornia No Drawing. Application July 11, 1955, Serial No. 521,418 7 Claims. (Cl. 252-138) This invention relates to detergent compositions suitable for use in aqueous media, and in particular relates to detergent compositions comprising certain allcyl sulfoxides as an essential active ingredient.

In U. S. Patent No. 2,658,038 it is disclosed that certain disulfoxides, viz, alpha, delta-dithiaalkane-bis-oxides, such as 3-hexyl-2,S-dithiahexane-bis-(2,5-dioxide), are surface active and are adapted to use as detergents in aqueous media. insofar as is known, however, no monosulfoxide has ever been reported to have detergent properties. The present invention is based on the discovery that certain long chain alkyl monosulfoxides possess a high degree of surface activity and have even greater detergent properties than the more complicated disulfoxides described in the aforesaid patent. This discovery is particularly surprising in view of the fact that such monosulfoxides possess only half as many functional groups and are indicated generally to be insoluble in water. They are unaifected by alkaline earth and heavy metal ions and hence are adapted to use in hard Water.

The monosulfoxide compounds which are employed in the detergent compositions provided by the invention correspond to the general formula:

wherein R represents a methyl or ethyl group and R represents an alkyl group containing at least 6, preferably 9-22, carbon atoms. Examples of such compounds include methyl hexyl sulfoxide, methyl heptyl sulfoxide, methyl nonyl sulfoxide, methyl dodecyl sulfoxide, methyl cetyl sulfoxide, ethyl octyl sulfoxide, ethyl decyl sulfoxide, ethyl tetradecyl sulfoxide, ethyl octadecyl sulfoxiu'e, ethyl eicosyl sulfoxide, etc. Mixtures of such compounds, e. g., mixed methyl alkyl sulfoxides in which the alkyl groups contain an average of 10-12 carbon atoms, are also suitable for use in accordance with the invention, and in fact constitute a preferred group within the above defined general class.

The members of the present class of sulfoxides are readily prepared by reacting methyl or ethyl mercaptan, or a mixture thereof, with an olefine or mixture of olefines to obtain an intermediate dialkyl sulfide, and thereafter oxidizing the latter to obtain the corresponding sun foxide. The reactions involved may be expressed by the following equations:

wherein R and R have the meanings stated above and C=C-R" represents an olefine containing at leash" 6 carbon atoms. Both of these reactions are well known,

former such as an azo-nitrile', The olefine reactant-may 0 States Patent Patented Apr. 2, 1957 be a pure olefine with the double bond occupying any position along the length of the carbon chain, or it may be a mixture of olefines such as is obtained by cracking paraffin wax or other petroleum hydrocarbon. It may also be a polymer, e. g., di-isobutylene, propylene trimer, propylene tetramer, etc. Olefines in which the double bond is in the alpha beta position are preferred since with the use of free radical catalysts they give rise to straight chain alkyl sulfoxides which have superior detergent activity. The oxidation reaction, whereby the intermediate dialkyl sulfide is converted into the corresponding sulfoxide, is conveniently carried out in the liquid phase at temperatures of about l0l20 C., employing hydrogen peroxide or nitric acid as the oxidizing agent. The reaction conditions are controlled in the known manner to avoid proceeding beyond the sulfoxide stage and forming sulfones which have no detergent properties.

The following example illustrates a typical preparation of one of the alkyl sulfoxide products of the present class, but is not to be construed as limiting the invention:

Example 1 pressure. T his material is then added with care to a molar Reaction occurs. readily at room temperature to form the corresponding excess of 70% aqueous nitric acid.

sulfoxide. Methylene chloride is added to the reaction mixture, and the solvent layer is separated and distilled. Methyl decyl sulfoxide is obtained as a crystalline whitesolid melting at 5253 C.

While the alkyl sulfoxides of the present class may be employed per so as detergents in aqueous media, their effectiveness is considerably enhanced by combining them with certain alkali-metal salts, viz, the sulfates, carbonates, silicates, phosphates and borates of sodium, potas glue may be employed to improve dirt suspending properties, and other synthetic detergents such as sulfonate soaps, sulfated fatty alcohols, quaternary ammonium compounds, polyethylene oxide esters of resin or fatty acids, etc. may be employed as detergency supplements.

In general, any of the materials commonly employed in detergent compositions as adjuncts to the essential active ingredient may be employed informulating the compositions of the present invention. Common among such adjuncts are perfumes, bactericides, foam stabilizer, abrasives, coloring or bluing agents, etc.

The following examples will illustrate a number of ways in which the principle of the invention may be applied, but are not to be construed as limiting the same.

Example 2 Percent by wt. Methyl dodecyl sulfoxide 25.0 Sodium sulfate 25.0

Carboxymethylcellulose 2.0

Water 48.0

1 Alkyl groups average 6-9 carbon atoms.

Carboxymethylceliulose 1.0 Water 89.0

1 Alkyl groups average 10-12 carbon atoms.

Example 7' Percent by wt. Ethyl octadecyl sulfoxide 25.0 Polyethylene oxide ester of tall oil 25.0 Carboxymethylcellulose' 3.5 Water 46.5

Example 8 Percent by wt. Mixedmethyl alkyl sul'foxides 1 10.0 Sodium sesquicarbonate. 20.0 Tetrasodium pyrophosphate 15.0 Sodium tripolyphosphate 15.0 Sodium metasilicate 40.0

1 Alkyl groups average 6-9 carbon atoms.

Example 9 Percent by wt. Methyl decyl sulfoxide 10.0 Trisodium phosphate 50.0 Sodium hydroxide 40.0

Example 10 Percent by wt. Ethyl dodecylv sulfoxide 10.0 Pine oil 2.5 Water 87.5

Example 11 Percent by wt. Methyl tripropyl sulfoxide 1 '15. Alkyl dimethylbenzyl ammonium chloride 10.0 Sodium silicate, 60 B Trisodium. phosphatelrepared irom propylene trim er.

As will be apparent from the foregoing specific examples, the detergent compositions provided by the invention may take the form of powders, liquids or pastes and may be formulated so as to be adapted to use as heavyor light-duty laundry detergents, dishwashing compositions, heavy-duty metal cleaners, dairy cleaners, paint removers; metal degreasing compounds, lloor cleaners, textile scouring compositions, shampoos, automobile washing compounds, and the like. As a demonstration of the effectiveness of the present class of sulfoxidcs in the form of a typical laundry powder, the following composition was prepared:

Percent by wt.

Tetrasodium pyrophosp Sodium metasilicates. Sodium sulfate b- CA: 9 2 5:?? ternmm The alkyl groups in'tlie sulfoxides ranged from C7 to C12. A washing solution was prepared by adding 1.65 grams of the composition to 1 50 cc. of distilled water, and the solution was heated to F. and placed in a closed container with a standard soiled cotton cloth swatch. The container and contents were agitated on a revolving rocking machine for 15 minutes, after which the solution was poured off and the cloth was removed from the container and squeezedby hand. The cloth was then replaced in the container and was rinsed by agitating for 5 minutes in distilledwater which had been heated to 120 F; The rinse water was then poured off, excess water was s'q'u'eez'ed from the cloth, and the latter was dried in the open air. The dry cloth was then examined under a reflectometer. The foregoing procedure was repeated employing washing solutions consisting of 1.65 grams of. various other compounded detergents and commercial washing compounds: dissolved in cc. of water. The refiectometer values were as follows:

Detergent Composition i Alkylaryl-polyether alcohol manufaet'ured bvltohm dz'Haas Co.

B Polvethvle'ne gl'ycbl' ester of Jauric acid manufactured by Alrosc OhemiealCo; p

3 Polvethvlene oxide manufactured by General Aniline Co.

4 Built sodium alkyl arylsullon'ato' manufactured by Lever Bros.

' Polyoxyethylene ether manufactured by Monsanto Chemical Co.

While the ability to form foam or suds is not necessarily areformulated for hQusehold-use-have the property of forming latgequantit-iesofthicle stable suds. The alkyl sulfoxides of thepresentclass possess this property to a high degree even though they are of the non-ionicty'pe of detergents-which, as a general rule, are notably poor sudsers The following table sets forth the lather values of 0.15% aqueous. solutions; of several of thesulfoxides of the presentclase. as determiuedby the standard Ross- Mil'es'te'st described at pages 77-79 of Synthetic Detergents by John W. McCutcheon (MacNair-Dorland, 1950):

soluble salt selected from the class consisting of the alkalimetal sulfates, carbonates, silicates, phosphates, borates, and mixtures thereof.

Lather Value at 25 C. Lather Value at 120 F.

Detergent Tested 1e 30 1 0 0 5 30 10 S80. SE0. SE0. SE0. min. S00. S00. S90. S00. 1111B.

Mixed methyl alltyl sulioxldes 7.0 7.0 7.0 7.0 7.0 25 25 25 Mixed methyl alkyl sulfoxides 22 22 22 21.5 22 21.5 21.5 21.5 21.5 Mixed methyl alkyl sulfoxldcs 9.0 8.8 8.8 8.8 8.8 22 22 22 21.5 12.5

1 Alkyl groups contained 10-12 carbon atoms. 9 Alkyl groups contained 7--l2 carbon atoms. 3 Equal parts of and In addition to their detergent properties, the sulfoxides on 2. A composition according to claim 1 wherein the of the present class are also excellent wetting agents. alltyl group represented byRis methyl. When tested by the Draves-Clarkson Sinking Time Test 3. A composition according to claim 1 wherein the (described at pages 6975 of the aforesaid McCutcheon alkyl group represented by R contains from about 9 to book) they consistently give sinking time values of about about 22 carbon atoms. l2-16 seconds in 0.l5 percent concentration in distilled 4. A composition according to claim 1. containing a water. Also, as will be apparent from the following data, they effect a great reduction on the surface tension of water:

1 Prepared from propylene trimer. i Allryl groups contained 6-9 carbon atoms. 9 Alkyl groups contained 10-12 carbon atoms.

Other modes of applying the principle of my invention may be employed instead of those explained, change being made as regards the materials or methods employed provided the steps or composition stated by any of the following claims, or the equivalent of such stated steps or compositions, be employed or obtained.

I, therefore, particularly point out and distinctly claim as my invention:

1. A detergent composition comprising between about 5 and about 40 percent by weight of a dialkyl sulfoxide of the general formula wherein R represents an alkyl group selected from the class consisting of methyl and ethyl and R represents an alkyl group containing from about 6 to about 22 carbon atoms, and at least about percent by weight of waterdirt-suspending amount of sodium carboxymethylcellulose. 5. A detergent composition comprising between about 5 and about 40 percent by weight of a mixture of dialltyl sulfoxides of the general formula wherein R represents an alkyl group selected from the class consisting of methyl and ethyl and R represents an alkyl group containing from about 6 to about 22 carbon atoms, and at least about 30 percent by weight of watersoluble salt selected from the class consisting of the alkalimetal sulfates, carbonates, silicates, phosphates, borates, and mixtures thereof.

6. A detergent composition comprising between about 5 and about 40 percent by weight of a mixture of methyl alkyl sulfoxides in which the alkyl groups contain from about 9 to about 22 carbon atoms and correspond to the olefines obtained by cracking paraffin wax and at least about 30 percent by weight of a water-soluble salt selected from the class consisting of alkali-metal sulfates, carbonates, silicates, phosphates, borates, and mixtures thereof.

7. A composition according to claim 6 wherein the said alkyl groups of said methyl alkyl sulfoxides contain from 59 about 10 to about 12 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 2,515,120 Harman July 11, 1950 2,654,667 Goodhue Oct. 6, 1953 2,658,038 Proell Nov. 3, 1953 FOREIGN P. TENTS 204,845 Switzerland Sept. 1, 1939 60 

1. A DETERGENT COMPOSITION COMPRISING BETWEEN ABOUT 5 AND ABOUT 40 PERCENT BY WEIGHT OF A DIALKYL SULFOXIDE OF THE GENERAL FORMULA 